Tumor burden in Hodgkin's lymphoma: much more than the best prognostic factor.

The intense immunological crosstalk between the rare neoplastic cells and the prevalent reactive ones is responsible for the development of signs and symptoms of Hodgkin's lymphoma. It is likely the reason for the superior predictivity constantly demonstrated by the tumor burden, as the final expression of the whole cytological disorder. Moreover, the tumor burden is related to the probability of response and its 1-year stability, showing different relationships according to the treatment administered. The relative risk of early treatment failure can be predicted on the basis of the tumor burden at diagnosis and the therapy chosen. Tumor burden is measured from the diagnostic whole body computed tomography (CT) scan, but can also be indirectly calculated from some staging parameters when the CT-aided assessment cannot be performed. Preliminary promising results have been obtained with a semi-automatic positron emission tomography/CT scan measuring metabolically active volumes, instead of whole visible masses.